You'd need a similar moment of inertia. Easiest would probably be to use a gear train to drive the secondary rotor, like the gearing in counter-rotating airscrews. OTOH having it grinding away for months would raise lube, losses and wear issues... I suppose they could have had two primary rotors and divided everything between them...
Ever read 2010, where they go back to Discovery after 10 years to find that the carousel bearings have slowly seized, so that the entire craft is spinning end over end?
BTW, did you notice the lack of Coriolis force when they were merrily zooming back and forth in the tunnel? Tut. I liked that they showed it in The
Expanse.
Oh, and a previously-unnoticed moon of Jupiter with mass similar to that of Earth? Even Galileo would have spotted that. Have to wonder, too, what radiation levels would have been that close to Jupiter.